Fotodiox EOS lens adapter for NEX question

I just received an EOS to NEX adapter from Fotodiox and have 2 basic questions.

1. I put a Canon Lens on the adapter but can't figure out how to take the adapter off. There is a little red button (I think it is a button), but I can't push it in or move it in any way so it doesn't do anything. I see a little metal "thing" that protrudes and thought that maybe I could push it, pull it or move it in some way and then remove the lens but that didn't work either. Any thoughts (the lens is a CAnon Lens EF 50mm)

2. When I did put the adapter/lens on the camera, I received a message saying that the camera didn't recognize the lens- so I was not able to take a photo. Is there a setting ont the NEX-7 that would override the message and allow photos to be taken?

Thanks very much. I have seen many posts about people using lens adapters and various lenses so I thought I'd try it.

Rick

P.S. I'm enjoying the camera very much. However, I haven't fully gotten the hang of the focusing system.